Great stuff folks. My budget really isn't unlimited, but it is about 30k per year on all marketing related expenses. And as things work out, most of the "work" I do is taken out of others budgets - admissions, alumni, etc. So, since I have the money sitting there, they will move it elsewhere if I don't use it. With that said and because photography is a big part of what I do, I've been spending it mostly on equipment.
With all the advice here, I think what will help in what I need to capture is either the 5D (if I can swing it) or the 30D AND the 50/1.4 & 24-70/2.8L. I'm going to sell the 300D and keep the 18-125 because I really like that lense and the results I have with it. I'm also going to keep the 50-500 sigma because for what I need it for it does just fine and the results are great. I'll also be ditching the sigma 70-300 because between the sigma 50-500 and canon 70-200 I can get both field and gym sports without having to worry about focal length and/or a wide enough aperature for low light situations in the gym.
So hopefully, by mid-summer, my signature will look like this:
30D/5D & 20D
Canon 70-200 f/2.8
Canon 50/1.4
Canon 24-70/2.8L
Sigma 18-125 f/3.5
Sigma 50-500 f/4
I won't be able to sell the 20D just yet because it'll have to wait until next year. So, maybe I get the 30D in the summer and when this time next year rolls around I ditch the 20D for a 5D.